The place where optimism most flourishes is the lunatic asylum.

The greatest task before civilization at present is to make machines what they ought to be, the slaves, instead of the masters of men.

Still, whether we like it or not, the task of speeding up the decrease of the human population becomes increasingly urgent.

There is a very intimate connection between hypnotic phenomena and religion.

Socialism also brings us up against the hard rock of eugenic fact which, if we neglect it, will dash our most beautiful social construction to fragments.

What we call 'morals' is simply blind obedience to words of command.

Courtship, properly understood, is the process whereby both the male and the female are brought into that state of sexual tumescence which is a more or less necessary condition for sexual intercourse. The play of courtship cannot, therefore, be considered to be definitely brought to an end by the ceremony of marriage; it may more properly be regarded as the natural preliminary to every act of coitus.